The present application claims priority under 35U.S.C. 119 to Japanese Patent Applications Nos. 2000-336766, 2001-50087 and 2001-307115, filed Nov. 2, 2000, Feb. 26, 2001 and Oct. 3, 2001, respectively, entitled xe2x80x9cFuel Tank Connectorxe2x80x9d. The contents of these applications are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to a fuel tank connector, in particular a connector capable of effectively decreasing leakage of evaporative emissions from a fuel tank.
2. Discussion of Background
As shown in FIGS. 23 and 24, a fuel tank 100 usually has a pipe 101, such as a fuel feeding pipe and a pipe for guiding gas generating from the fuel, connected thereto. The connection of the pipe 101 is made by use of a connector 110 fitted to the fuel tank 100 as shown in FIGS. 23 and 24.
The connector 110, which is shown in FIGS. 23 and 24, includes a tubular portion 111 for connection with the pipe 101, a flanged portion 112 projecting laterally from a peripheral portion of one end of the tubular portion 111 melt-bonded to the tank 100 so as to cover an opening 100a in the tank 100, and a fuel cutoff valve 113 provided in the flanged portion 112 on a side opposite the tubular portion 111. The tubular portion 111 and the flanged portion 112 are integrally molded from high-density polyethylene.
The fuel cutoff valve 113 in the shown connector 110 includes a float chamber forming box 113b formed in a cylindrical shape, having a valve seat unit 113a with a valve seat 113axe2x80x2 at the opening of a bore in communication with a bore in the tubular portion 111, having a bottom opened and made of polyacetal; a float 113c having an upper portion integrally formed with a valve 113e and housed in the box 113b so as to be slidable therein; and a lid 113d closing the opened bottom of the box 113b and cooperating with the box to form the float chamber with the float 113c incorporated therein. As the float 113c rises, the valve 113e makes close contact with the valve seat 113axe2x80x2 to close the opening.
In the connector 110, the box 113b of the fuel cutoff valve 113 is configured to be integrally fitted to the flanged portion 112 so as to have an upper side of the box 113b embedded in the flanged portion 112 by, e.g., plastic molding wherein the box is integrally united to the flanged portion with the box being inserted in a mold. A peripheral portion of the flanged portion 112 with the box 113b is melt-bonded to a surface of the tank 100 around the opening 100a of the tank 100 with the box 113b being inserted into the tank 100 through the opening 100a of the tank 100.
In the connector 110 thus configured, the flanged portion 112 and the tubular portion 111 are made of high-density polyethylene. The evaporative emissions generating from the fuel in the tank 100 or another member have been predicted to leak out, though at a regulated value or less, through a portion of the flanged portion 112 provided between an edge of the opening 100a of the tank and the box 113b of the connector 110 melt-bonded to the tank 100.
It is an object of the present invention to provide an easy-to-mold connector capable of effectively decreasing leakage of evaporative emissions from a fuel tank, which is predicted in the conventional connector.
In order to attain the object, according to a first aspect of the present invention, there is provided a fuel tank connector adapted to be fitted to an opening of a fuel tank to connect the fuel tank and a pipe in communicating fashion, comprising:
a gas barrier member made of a synthetic resin having a gas barrier property, the gas barrier member including a tubular portion and a flanged portion provided on a peripheral side of the tubular portion and having a greater side than an opening of the fuel tank;
wherein the gas barrier member is made of polybutylene terephthalate, polyphenylene sulfide, a liquid crystal polymer, aliphatic polyketone, aromatic polyamide, a blended polymer of an ethylene-vinyl alcohol copolymer and high-density polyethylene, a blended polymer of polyamide and polyethylene, a blended polymer of polyamide and high-density polyethylene, or polyethylene terephthalate;
the gas barrier member has at least a portion of a surface covered with an outer shell made of an olefin resin having an adhesive property, polyethylene or high-density polyethylene; and
the outer shell includes an annular projected portion, which covers a leading end of the flanged portion and projects toward an outer surface of the fuel tank.
The fuel tank connector thus constructed can effectively minimize that evaporative emissions deriving from the fuel in the fuel tank leak from the connector.
Additionally, the gas barrier member with the outer shell can be melt-bonded to the fuel tank at the outer shell in reliable and easy fashion.
With regard to a fuel tank with an outer surface layer made of high-density polyethylene, the connector can be fitted to the fuel tank through the annular projected portion of the outer shell with high bonding strength maintained, effectively minimizing the leakage of the evaporative emissions from the fuel tank by the gas barrier member.
In order to attain the object, according to a second aspect of the present invention, the flanged portion has a peripheral portion melt-bonded to a synthetic resin having a gas barrier property and forming a fuel tank to fit the connector to the fuel tank, in the first aspect.
The fuel tank connector thus constructed can further effectively minimize the leakage of the evaporative emissions from the fuel tank, in addition to the advantages stated earlier.
In order to attain the object, according to a third aspect of the present invention, at least a portion of the outer shell made of an olefin resin having an adhesive property, and at least a portion of a surface of the gas barrier member uncovered with the outer shell are covered with an additional outer shell made of high-density polyethylene, in the first or the second aspect.
In the fuel tank connector thus constructed, the outer shell, which is made of high-density polyethylene, can be fitted to the gas barrier member in easier and more reliable fashion, allowing the connector to be fitted to the fuel tank in more reliable and easier fashion, in addition to the advantages stated earlier.
In order to attain the object, according to a fourth aspect of the present invention, the gas barrier member has the leading end of the flanged portion provided with an annular projected portion, which projects toward the outer surface of the fuel tank, in the first, the second or the third aspect.
In the fuel tank connector thus constructed, design freedom in fitting of the connector to the fuel tank can increase in such a manner to effectively minimize the leakage of evaporative emissions from the fuel tank in addition to the advantages stated earlier.
In order to attain the object, according to a fifth aspect of the present invention, the gas barrier member has the leading end of the flanged portion provided with an annular projected portion, which projects toward the outer surface of the fuel tank, and the connector has the annular projected portion melt-bonded to the outer surface of the fuel tank, thereby being fitted thereto, in the first aspect.
With regard to a fuel tank with an outer layer made of high-density polyethylene, the fuel tank connector thus constructed can be fitted to the fuel tank through the annular projected portion of the outer shell and the annular projected portion of the gas barrier member with high bonding strength maintained, effectively minimizing the leakage of evaporative emissions from the fuel tank by the gas barrier member.
In order to attain the object, according to a sixth aspect of the present invention, one of the annular projected portion of the outer shell and the leading end of the flanged portion of the gas barrier member has a projection formed thereon, and the outer shell is fitted to the gas barrier member with the projection being inserted into the other one without the projection, the outer shell being made of polyethylene or high-density polyethylene, in the first aspect.
The fuel tank connector thus constructed can ensure to maintain the unity of the annular projected portion provided on the leading end of the flanged portion of the gas barrier member and the annular projected portion of the outer shell at high level.
In order to attain the object, according to a seventh aspect of the present invention, the gas barrier member has the leading end of the flanged portion provided with an annular projected portion, which projects toward the outer surface of the fuel tank and has a projecting length substantially equal to that of the annular projected portion of the outer shell, and the annular projected portion of the gas barrier member and the annular projected portion of the outer shell has a cavity formed therebetween to be opened on a side of the outer surface of the tank, the outer shell made of polyethylene or high-density polyethylene, in the first aspect.
In the fuel tank connector thus constructed, when the annular projected portion of the outer shell is heat-melted, the melted material of polyethylene or high-density polyethylene forming the annular projected portion can get into the cavity to melt-bond the annular projected portion to a fuel tank, spreading the melted material of polyethylene or high-density polyethylene in a wide range.
When the melt-bonding is carried out to leave some part of the cavity unfilled after having melt-bonded the annular projected portion of the outer shell to the fuel tank, the unfilled part can absorb the expansion of the gas barrier member, which could be caused by fuel or evaporative emissions from the fuel. This arrangement can make it difficult for a force lowering the melt-bonding strength to be applicable to the melt-bonded portion between the annular projected portion of the outer shell and the fuel tank.
In order to attain the object, according to an eighth aspect of the present invention, the gas barrier member has the leading end of the flanged portion provided with an annular projected portion, which projects toward the outer surface of the fuel tank and has a smaller projecting length substantially than the annular projected portion of the outer shell, the outer shell being made of polyethylene or high-density polyethylene, in the first aspect.
In the fuel tank connector thus constructed, when the annular projected portion of the outer shell is heat-melted, the melted material of polyethylene or high-density polyethylene forming the annular projected portion can get into between a projecting surface of the annular projected portion of the gas barrier member and the outer surface of the fuel tank to melt-bond the annular projected portion of the outer shell to the fuel tank, spreading the melted material of polyethylene or high-density polyethylene in a wide range.
In order to attain the object, according to a ninth aspect of the present invention, the gas barrier member, which is covered with the outer shell, has an upper side stepwise formed so as to have a stepped surface facing the leading end of the flanged portion of the gas barrier member, the outer shell made of polyethylene or high-density polyethylene, in the first aspect.
In the fuel tank connector thus constructed, even if the gas barrier member is swollen by fuel or evaporative emissions from the fuel, the force caused by the swell can be received by an opposed surface of the outer shell (made of polyethylene or high-density polyethylene) in contact with the stepped surface to be dispersed. This arrangement can make it difficult for a force lowering the melt-bonding strength to be applicable to the melt-bonded portion between the annular projected portion of the outer shell and the fuel tank.
In order to attain the object, according to a tenth aspect of the present invention, the fuel tank connector is used for connection with a fuel feeding pipe in the first, the second, the third, the fourth, the fifth, the sixth, the seventh, the eighth or the ninth aspect.
The fuel tank connector thus constructed can connect the fuel feeding pipe to the fuel tank in such a manner to effectively minimize the leakage of evaporative emissions from fuel, in addition to the advantages stated earlier.
In order to attain the object, according to an eleventh aspect of the present invention, the fuel tank connector is used for connection with a vent pipe in the first, the second, the third, the fourth, the fifth, the sixth, the seventh, the eighth or the ninth aspect.
The fuel tank connector thus constructed can connect the vent pipe to the fuel tank in such a manner to effectively minimize the leakage of evaporative emissions from fuel, in addition to the advantages stated earlier.
In order to attain the object, according to a twelfth aspect of the present invention, the fuel tank connector further comprises a fuel cutoff valve in the first, the second, the third, the fourth, the fifth, the sixth, the seventh, the eighth or the ninth aspect.
The fuel tank connector thus constructed can connect a pipe to the fuel tank through the fuel cutoff valve, effectively minimizing the leakage of evaporative emissions from fuel, in addition to the advantages stated earlier.
As explained, the fuel tank connector according to the present invention, which is adapted to be fitted to an opening of a fuel tank to connect the fuel tank and a pipe in communicating fashion, comprises the gas barrier member made of a synthetic resin and having a gas barrier property, the gas barrier member including the tubular portion and the flanged portion provided on the peripheral side of the tubular portion and having a greater side than the opening of the fuel tank; wherein the gas barrier member is made of polybutylene terephthalate, polyphenylene sulfide, a liquid crystal polymer, aliphatic polyketone, aromatic polyamide, a blended polymer of an ethylene-vinyl alcohol copolymer and high-density polyethylene, a blended polymer of polyamide and polyethylene, a blended polymer of polyamide and high-density polyethylene, or polyethylene terephthalate. This arrangement can effectively minimize that evaporative emissions deriving from the fuel in the fuel tank leak from the fuel tank connector.